Selective and efficient removal of perrhenate by an imidazolium based hexapodal receptor in water medium.

This work reports a new cationic imidazolium based hexapodal receptor, [L.6Br], for selective and efficient removal of perrhenate (ReO4-) as [L.6ReO4] from 100% aqueous medium via extraction through precipitation. Selective removal of ReO4- even in the presence of common anions such as halides and oxyanions in excess within a wide range of pH values from 1 to 14 by this receptor is also demonstrated. Importantly, [L.6Br] could easily be recovered upon heating [L.6ReO4] with tetrabutylammonium bromide (TBABr) in acetonitrile at 60 °C and recycled as a fresh extractant for ReO4-.